Method and an electro-beam furnace for ingot production

ABSTRACT

The method of the present invention provides for melting a metal charge in an electron-beam furnace over a tundish and for solidifying molten metal in a mould the capacity of which is increased in a horizontal direction as it is filled with hot metal. The capacity of the mould is increased by moving its trough-shaped casing in a horizontal plane relative to its internal partition. In order to produce multi-layer ingots, the internal partition is lifted for a distance equal to the thickness of the previous solidified layer of the ingot. Electron-beam surface for realizing this method includes a vacuum chamber, a charger, and electron guns.

United States Patent [1 1 Paton et al. I

METHOD AND AN ELECTRON-BEAM FURNACE FOR INGOT PRODUCTION Filed: May 3,1971 Appl. No.: 139,464

Foreign Application Priority Data June 15, 1970 U.S.S.R 439143 June 15,1970 U.S.S.R 1439144 US. Cl 164/50, 118/495, 141/283,

[4 1 July 31,1973

[51] Int. Cl 822d 27/02 [58] Field of Search 164/50, 250, 84, 164/85,87, 88, 136, 276, 335; 219/60 A, 60

Primary Examiner.l. Spencer Overholser Assistant ExaminerJohn E. RoethelAttorney-l-Iolman & Stern [5 7 ABSTRACT The method of the presentinvention provides for melting a metal charge in an electron-beamfurnace over a tundish and for solidifying molten metal in a mould thecapacity of which is increased in a horizontal direction as it is filledwith hot metal. The capacity of the mould is increased by moving itstrough-shaped casing in a horizontal plane relative to its internalpartition. In order to produce multi-layer ingots, the internalpartition is lifted for a distance equal to the thickness of theprevious solidified layer of the ingot. Electronbeam surface forrealizing this method includes a vac uum chamber, a charger, andelectron guns.

4 Claims, 1 Drawing Figure METHOD AND AN ELECTRON-BEAM FURNACE FOR INGOTPRODQCTION The present invention relates to methods for ingot productionand to electron-beam furnaces for the realization of these methods.

In the prior art, there is known a method for ingot production bymelting a metal charge in an electronbeam furnace over aconstant-capacity tundish and a variable-capacity mould.

Also known in the prior art is an electron-beam furnace for therealization of this method, comprising a vertical mould whose capacitycan be varied by moving or lowering a dummy-bar relative to thestationary mould. In these electron-beam furnaces, the metal charge ismelted over either the mould r or a tundish from which the molten metalis transferred into the mould. n solidification, one obtains round orsquare ingots which have to be forged into flat slabs before they can bemade into sheets. in electron-beam furnaces using these prior-artmoulds, it is impossible to obtain ingots in the form of flat slabs andto avoid the expensive operation of forging or rolling the'ingots intoflat slabs. Nor can these electron-beam furnaces produce multi-layercast slabs. Furthermore, in the priorart methods, ingots are pulled outof the mould, and this results in tears and cracks on the surface of theingot, impairing its quality.

It is an object of the present invention to avoid the above-mentioneddisadvantages.

The present invention is directed to providing a method for ingotproduction and an electron-beam furnace for the realization of thismethod which will cut down the cost of slab production for sheets byproducing cast slabs for sheets directly in the electron-beam furnace.The invention also aims to improve the surface quality of the resultantflat slabs, including multi-layer slabs.

With these objects in view, the present invention relates to a methodfor ingot production by melting a metal charge in an electron-beamfurnace having a constant-capacity tundish and a variable-capacitymould, in which, according to the invention, the capacity of the mouldis increased in a horizontal direction as it is filled with hot metal.This method cuts down the cost of slab production for sheets byeliminating the forging or rolling of ingots into flat slabs prior tosheet production.

It is preferable to increase the capacity of the mould by moving itstrough-shaped casing in a horizontal plane relative to its internalpartition. This improves the quality of the ingots by eliminating theformation of cracks and tears in the skin of the ingot.

To form the next layer of the ingot, the internal partition can belifted for a distance equal to the thickness of the previous solidifiedlayer of the ingot, and the mould can be brought back to its startingcapacity, after which the feed of hot metal can be resumed. Thus it ispossible to produce multi-layer slabs.

To realize the method, an electron-beam furnace has been designed,including a vacuum chamber fitted with a charger and enclosing electronguns, at water-cooled tundish, and a water-cooled mould, in which,according to the invention, the mouldis made in the form of atrough-shaped receiver mounted so that it can be moved in a horizontalplane relative to an internal partition fastened inside the vacuumchamber.

This type of furnace cuts down the cost of production of slabs forsheets, since cast slabs for sheets are produced directly in thefurnace, so that the foregoing or rolling of ingots prior to sheetproduction can be dispensed with. This furnace also improves the qualityof the ingot surface.

It is preferable to fasten the internal partition of the trough-shapedreceiver in the vacuum chamber so that it can be lifted for a distanceequal to the depth of the trough-shaped receiver thus making it possibleto produce multi-layer cast slabs.

The invention will be more fully understood from the followingdescription of a preferred embodiment of an electron-beam furnace forthe realization of the method disclosed herein, when read in connectionwith the accompanying drawing which shows a perspective view incross-section of an electron-beam furnace.

Referring to the drawing, there is shown an electronbeam furnace whichhas a vacuum chamber 1 fitted with a device not shown in the drawing tocharge the metal 2 to be melted and enclosing electron guns 3, 4 and 5.Within the melting zone of the charge 2 there is a tundish 6 made fastto the vacuum chamber 1 of the electron-beam furnace. The bottom of thevacuum chamber 1 has a rail track 7 on which is riding a trolley 8coupled by a tie-bar to a reciprocating mechanism-- not shown in thedrawing-which actuates the trolley in a horizontal plane. Thereciprocating mechanism can have a mechanical or a hydraulic drive. Thetrolley 8 carries a trough-shaped receiver 10 with a transverse internalpartition 11 coupled by hollow tie-bars 12 to a lifting mechanism-notshown in the drawing-which lifts the partition. The lifting mechanismcan have a mechanical or a hydraulic drive. Cooling water is fed intothe tundish 6 by means of hollow tie-bars 13, into the trough-shapedreceiver 10 by means of hollow tiebars 14, and to the internal partition1 l by means of the hollow tie-bars 12.

The electron-beam furnace for realizing the method according to theinvention operates as follows:

The charger-not shown in the drawing-feeds the source material 2 intothe melting zone where it melts under the action of the electron gun 3.The molten metal 2 trickles into the tundish 6 where it is furtherheated by the electron gun 4 and from which it overflows into thehorizontal trough-shaped receiver 10.

In the starting position of the trough-shaped receiver 10, its minimuminitial capacity is limited by the internal partition 11 and the endwall 15 of the receiver 10, brought close to it.

The metal collected in the receiver 10 is heated by the electron gun 5.As the initial capacity of the receiver 10 is filled with hot metal, thetrolley 8 carrying the receiver 10 is moved to the right, which, in theembodiment in question, is carried out by a reciprocating mechanism notshown in the drawing. The reciprocating mechanism may have a mechanicalor a hydraulic drive. As a result of this movement, the distance betweenthe internal partition 11 and the end wall is of the receiver 10 isincreased, and molten metal fills the increased capacity of the receiver10. On leaving the zone illuminated by the electron gun 5, the metalcools and begins to solidify away from the end wall 15 towards thepartition 1 1 of the receiver 10. This produces the first layer 16 of aningot. After the first layer 16 of the ingot has been formed, theelectron guns 3, 4, and 5 are turned off, the internal partition islifted for a distance equal to the thickness of the first solidifiedlayer 16 of the ingot by a lifting mechanism-not shown in the drawing,and the receiver mounted on the trolley 8 in this embodiment is broughtback to its starting position by the reciprocating mechanism-not shownin the drawing-so that the wall is brought close to the partition 11.Then the electron guns 3, 4, and 5 are turned on again, and a secondlayer 17 of the ingot begins to be formed. This second layer may be madeof the same or any other metal, as desired.

The process described herein produces ingots in the form of flat slabswhich can readily be rolled into sheets.

We claim:

1. A method for the production of slab-like ingots, comprising the stepsof melting metal in an electronbeam furnace over a tundish; transferringthe molten metal from said tundish into a mold made in the form of atrough-like tray whose length is divided by a vertical partitionextending transverse said tray; moving said mold horizontally lengthwiserelative to said partition to increase the volume of the space to befilled with liquid metal; and pouring molten metal into said mold toform the slab-like ingot.

2. The method as claimed in claim 1, comprising the further steps ofvertically moving said partition to a height equal to the thickness of apreceding slab-like ingot; returning said mold to its initial position;and again pouring molten metal therein to form another layer of theslab-like ingot.

3. An electron-beam furnace for the production of slab-like ingotscomprising a vacuum chamber; charging means to supply said chamber withmetal to be remelted; electron-beam guns to melt said metal within saidelectron-beam furnace; a water-cooled tundish for molten metal locatedwithin said vacuum chamber; a mold in the form of a trough-like trayadapted to move lengthwise in a horizontal direction; a verticalpartition within said chamber adapted to enter the mold space of saidmold and transversely divide it; and means for moving said moldlengthwise in a horizontal plane relative to said partition so as toincrease the volume of the molding space.

4. The electron-beam furnace as claimed in claim 3, wherein saidpartition is adapted to move vertically relative to said mold, therebeing power means to accomplish this vertical movement.

i k III l

1. A method for the production of slab-like ingots, comprising the stepsof melting metal in an electron-beam furnace over a tundish;transferring the molten metal from said tundish into a mold made in theform of a trough-like tray whose length is divided by a verticalpartition extending transverse said tray; moving said mold horizontallylengthwise relative to said partition to increase the volume of thespace to be filled with liquid metal; and pouring molten metal into saidmold to form the slab-like ingot.
 2. The method as claimed in claim 1,comprising the further steps of vertically moving said partition to aheight equal to the thickness of a preceding slab-like ingot; returningsaid mold to its initial position; and again pouring molten metaltherein to form another layer of the slab-like ingot.
 3. Anelectron-beam furnace for the production of slab-like ingots comprisinga vacuum chamber; charging means to supply said chamber with metal to beremelted; electron-beam guns to melt said metal within saidelectron-beam furnace; a water-cooled tundish for molten metal locatedwithin said vacuum chamber; a mold in the form of a trough-like trayadapted to move lengthwise in a horizontal direction; a verticalpartition within said chamber adapted to enter the mold space of saidmold and transversely divide it; and means for moving said moldlengthwise in a horizontal plane relative to said partition so as toincrease the volume of the molding space.
 4. The electron-beam furnaceas claimed in claim 3, wherein said partition is adapted to movevertically relative to said mold, there being power means to accomplishthis vertical movement.